In order to use a desired service in a mobile network, a terminal (UE: User Equipment) needs to set up a user data packet path (which is referred to as a bearer (PDN connection), a protocol data unit (PDU) session, or the like) between the UE and a packet data network (PDN) corresponding to the service (see Patent Literature 1).
When a terminal does not use a service, it is not necessary to set up a user data packet path. Accordingly, in a conventional technique, a base station that manages the terminal determines an operation state of the user data packet path by monitoring whether there is a packet which is being transmitted or received through the user data packet path, and the user data packet path is released to an idle state when it is determined that the user data packet path is not operating.